1. Field of the Invention
The present invention relates generally to the field of musical drums, and more particularly to an improvement of a drum that enables modulation of the high and low pitches of the drum sounds to accurately simulate the authentic sounds of a variety of well-known ethnic and other types of drums.
2. Description of the Prior Art.
Musical drums have a rich and varied history. The shell portion of the drum comes in all shapes and sizes and has been fashioned from a variety of materials, including wood, fibrous material, metal and the like. Drumheads are typically made from animal skins or a synthetic substitute.
In the prior art, the sounds that drums produce will vary depending on a number of factors, including, without limitation, the size of the drum, the material composition of the shell, the material composition of the drumhead and the tautness of the head. All these factors can have a substantial affect on the tones and pitches and specifically the unique characteristics of the sounds that the drums produce. Once in place, the effect of any of these factors tend not to vary. Thus, a shell made of a certain kind of material will affect the tone or pitch produced by the drum due to the unique characteristics of that particular material. As long as that particular material composition remains intact, i.e., does not decay for any reason, or does not contain a defect, the contribution that the material makes to the drum sound will remain relatively constant. The same is true of the drumhead material, which also embodies its own unique characteristics. As long as the drumhead material remains relatively intact and the head maintained at a constant tautness, the effect that the drumhead has on the drum sounds and its unique sound characteristics will also remain relatively constant.
However, absent from the prior art is the means and structure to provide a drum system that is capable of producing a variety of unique drum sounds using a single instrument modified only by an interchangeable component. More specifically, this includes a unique resonating drum system that produces vibrations at a certain frequency (particularly bass tones) to simulate authentic drum sounds, including, for example, sounds produced by the African Djembe, the Middle Eastern Doumbek, the Japanese Shime Daiko and the Afro-Cuban Conga.
Many goblet and waisted style drums, such as the Doumbeks and Djembes, use what is known as the Helmholtz resonance system based on a resonator, which comprises a container or cavity with an open hole or neck.
The Helmholtz resonator is an example of an acoustic system which is useful when the desired wavelength is significantly larger than the physical dimensions of the system. Other familiar examples of Helmholtz resonators include blowing across the top of an empty bottle. Goblet and bowl shaped drums essentially work in the same manner as the empty bottle except the air is set in motion (in and out of the cavity and neck) by striking the drumhead instead of blowing air across the neck. Bowl or cavity shaped drums of the types described produce two pronounced sounds-high and low. High harmonics generally are enunciated from the drumhead itself and largely depend on how tight or taut the drumhead is. These higher pitched sounds radiate up and around from the drumhead. The bass tones emanate from the bottom of the drum and are produced by the “Helmholtz” resonator or cavity of the drum in conjunction with the neck. Resonant frequencies are determined by the radius of the neck, area of the neck, and length of the neck in conjunction with the speed of sound. The smaller neck diameter lowers the pitch or resonant frequency. However, there is no means to change the resonant frequency of these drums except by placing one's hand or arm up and inside the body to effectively lower the pitch. This technique obviously has its limitations. This unique resonance system is apparent in drums such as a small diameter (8″) Doumbek drum where a very low frequency is produced. There are no low resonant frequencies present when the drum is sitting on the floor, as it creates a “stopper” and does not allow the air to escape out and back through the neck or body. Certain drums are intentionally made closed so that no air can escape with the movement of the drumhead, such as a Japanese Shime Daiko drum or Japanese Hira Daiko Drum. Conga drums are sometimes played sitting flat on the floor thereby creating a “stopper” and eliminating the bass from the instrument.
The drum system of the present invention uses a unique and significantly improved resonating drum system consisting of a drum body in a rigid structure communicating by a removable threaded narrow neck (modulator tube) to the outside air. The frequency of resonance is determined by the volume of air, in and near the neck, resonating in conjunction with the compliance of the air in the cavity. The sustained bass tone is due to the ‘springiness’ of air: when you compress it, its pressure increases and it tends to expand back to its original volume.
In accordance with the present invention, musical drums with interchangeable resonant tubes, called “modulators” or “pitch modulators”, which vary in diameter and/or shape, effectively create long lasting and varying resonant bass tones. Each of these interchangeable components will produce a unique resonant frequency, independent of drumhead tension. The “stopper” sound described above is easily achieved by removing the threaded modulator tube and replacing it with the threaded plug.
Thus, the present invention comprises a single lightweight, portable, musical drum that is able to produce the unique characteristic sounds of a Conga, Djembe, Doumbek, and Shime Daiko drum simply with the use of detachably and interchangeably connecting changing the tubes or similarly-shaped structures and a “stopper” plug.